Tom de Saulles, building physicist, The Concrete Centre

1. Changes to Part L and the implications
for heavyweight buildings
Tom De Saulles
The Concrete Centre
Specifying Low Carbon Buildings
Southbank Centre
7 October 2010

2. Heat loss from
an average UK home
400 400
heat loss (W/K)
300 300
200 200
Base
year
100 100
0 0
1970 1970
2002 2006 2002
2010 2006
2013 2010
2016 2013

3. Heat loss from
an average UK home
400
+275%
heat loss (W/K)
300
200
Base
year
100
0
1970 2002 2006 2010 2013 2016

4. BRE Innovation Park
Brookwood farm, Woking
September 2010.
Code level 5, ICF construction.
(William Lacey Group)

5. Currently being updated
for Part L 2010, 2013
& 2016.

6. Meeting 2010, 2013
targets for Part L1
1. No additional features
(detached house)
2. Weather comp.
3. Weather comp. + WWHR
2010 (25%) 2013 (44%) 2016 (70%)
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR +Basic fabric spec.
FGHRS + PV (1kWp)
Walls: 0.25, floor: 0.18, roof: 0.13
windows: 1.5, air permeability: 5.0
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
Y-value: 0.08
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
% improvement over Part L 2006

7. Meeting 2010, 2013
targets for Part L1
(detached house)
1. No additional features
2. Weather comp. 2010 (25%) 2013 (44%) 2016 (70%)
3. Weather comp. + WWHR
Basic fabric spec.
Walls: 0.25, floor: 0.18, roof: 0.13
4. Weather comp. + WWHR + FGHRS
windows: 1.5, air permeability: 5.0
Y-value: 0.08
Enhanced fabric spec.
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
Walls reduced to 0.2
Y-value reduced to 0.05
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
% improvement over Part L 2006

8. Meeting 2010, 2013
targets for Part L1
(detached house)
2010 (25%) 2013 (44%) 2016 (70%)
1. No additional features
Basic fabric spec.
2. Weather comp.
Walls: 0.25, floor: 0.18, roof: 0.13
windows: 1.5, air permeability: 5.0
Y-value: 0.08
3. Weather comp. + WWHR
Enhanced fabric spec.
Walls reduced to 0.2
4. Weather comp. + WWHR + FGHRS
Y-value reduced to 0.05
Govt. fabric energy efficiency spec.
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
Walls: 0.18, windows: 1.4, floor: 0.18
roof: 0.13 air permeability: 3.0, Y-value: 0.05.
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
% improvement over Part L 2006

9. Flue gas heat recovery Waste water heat recovery
(about £600 for smaller dwellings) (from about £200)
• Zenex Gas Saver • Recoh-vert
• Ravenheat Energy Catcher • Recoh-tray
• Alpha Flowsmart • Enviroharvest
• Warmit (AK Industries),

10. Meeting 2010, 2013
targets for Part L1
(detached house)
+ Waste water heat recovery 2010 (25%) 2013 (44%) 2016 (70%)
1. No additional features
Basic fabric spec.
2. Weather comp.
3. Weather comp. + WWHR
Enhanced fabric spec.
4. Weather comp. + WWHR + FGHRS
Govt. fabric energy efficiency spec.
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
% improvement over Part L 2006

11. Meeting 2010, 2013 & 2016
targets for Part L1
(detached house)
+ Waste water heat recovery 2010 (25%) 2013 (44%) 2016 (70%)
+ Flue gas heat recovery features
1. No additional
Basic fabric spec.
2. Weather comp.
3. Weather comp. + WWHR
Enhanced fabric spec.
4. Weather comp. + WWHR + FGHRS
Govt. fabric energy efficiency spec.
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
% improvement over Part L 2006

12. WWHR = waste water heat recovery ■ 2016 zero carbon fabric spec. ■ Enhanced 2016 zero carbon fabric spec.
FGHR = Flue gas heat recovery
Part L: 2010 (25%) 2013 (44%) 2016 (70%?)
Flat, mid-storey 1. No additional features
(50m2) 2. Weather comp.
3. Weather comp. + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006
End terrace, 1. No additional features
2-storey (61 m2) 2. Weather comp.
3. Weather comp. + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006
Mid terrace, 1. No additional features
2-storey (61m2) 2. Weather comp.
3. Weather comp. + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006
End terrace,
1. No additional features
3-storey (125m2)
2. Weather comp. + 100mm cylinder insulation
3. Weather comp. + 100mm cylinder insulation + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1 kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006
Mid terrace,
1. No additional features
3-storey (125m2)
2. weather compensator + 100mm cylinder insulation
3. Weather comp. + 100mm cylinder insulation + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1 kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006
Detached, 1. No additional features
2-storey (127m2)
2. weather comp. + 100mm cylinder insulation
3. Weather comp. + 100mm cylinder insulation + WWHR
4. Weather comp. + WWHR + FGHRS
5. Weather comp. + WWHR + FGHRS + PV (1kWp)
6. Weather comp. + WWHR + FGHRS + PV (2 kWp)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
% reduction in CO2 emission over Part L1A 2006

13. Main findings
Part L1 2010 compliance:
• U-value for external walls, around 0.2 – 0.25 W/m2K
• Air permeability, around 5 m3/(h.m2)
• Renewables are not necessary, but enhancements to services are.

14. Main findings
Part L1 2010 compliance:
• U-value for external walls, around 0.2 – 0.25 W/m2K
• Air permeability, around 5 m3/(h.m2)
• Renewables are not necessary, but enhancements to services are.
Part L1 2013 compliance:
• Renewables can still be avoided, but a much higher level of fabric performance is needed.
• Alternatively, could use 2010 fabric performance and about 1 kW of PV.

15. Main findings
Part L1 2010 compliance:
• U-value for external walls, around 0.2 – 0.25 W/m2K
• Air permeability, around 5 m3/(h.m2)
• Renewables are not necessary, but enhancements to services are.
Part L1 2013 compliance:
• Renewables can still be avoided, but a much higher level of fabric performance is needed.
• Alternatively, could use 2010 fabric performance and about 1 kW of PV.
Part L1 2016 compliance:
• Need to meet or exceed the Govt. fabric energy efficiency standard. 2 - 3 kW of PV also needed.

16. Introduction of thermal mass into Part L1
Measured by the ‘K-value’ (KJ/m2/K)
This is the thermal capacity of the first
100mm, or up to the first insulating
layer, if this occurs first.
100mm

17. How much thermal mass
do floors and walls have?
Sandwich panel, Solid masonry, Brick & block, Woodcrete block, Hemcrete block, Insulating clay block,
Up to 230 kJ/m2K Up to 190 kJ/m2K Up to 190 kJ/m2K Up to 145 kJ/m2K Up to 135 kJ/m2K Up to 65 kJ/m2K
Frame construction Frame construction Block partition, Stud partition, Hollow core Beam & block
2 x plasterboard, 1 x plasterboard, Up to 100 kJ/m2K Up to 9 kJ/m2K upper floor, up to upper floor, up to
Up to 18 kJ/m2K Up to 9 kJ/m2K 120/160 kJ/m2K 120/40 kJ/m2K
Timber upper floor, Insitu-concrete Beam & block Timber ground floor,
up to 9/18 kJ/m2K ground floor, ground floor, up to 20 kJ/m2K
up to 140 kJ/m2K up to 110 kJ/m2K

18. Arup/Concrete Centre thermal properties tool

19. Heating season: daytime
Sun at midday
17º - 40º
South
Heating season: night-time

20. What difference can thermal mass
make in SAP 2009?
EXAMPLE:
Highly insulated, airtight semi-detached house with efficient heating and controls.
RESULT:
• Moving from low to high thermal mass reduces emissions by about 3-4%
• This is roughly the same as changing the external wall U-value from 0.2 to 0.15

21. New full fill insulation system
Achieves a U-value of 0.17 - 0.18 with a 100mm cavity

22. Summertime performance / overheating
• The Zero Carbon Hub is calling for
an improved overheating check that
must be passed by all new homes.

23. Summertime performance / overheating
• The Zero Carbon Hub is calling for
an improved overheating check that
must be passed by all new homes.
• The check should take account of
future climate change.
• It should also take proper account of
night cooling and thermal mass.

24. Free passive design tool (currently under development)

25. Part L2 (2010)
New drivers for passive cooling
• 25% reduction in emissions required by Part L2

26. Part L2 (2010)
New drivers for passive cooling
• 25% reduction in emissions required by Part L2
• 23% increase in the assumed CO2 emissions from electricity (Part L1 and L2)

27. Part L2 (2010)
New drivers for passive cooling
• 25% reduction in emissions required by Part L2
• 23% increase in the assumed CO2 emissions from electricity (Part L1 and L2)
• New limits for solar gain in Part L2

28. Part L2 (2010)
New drivers for passive cooling
• 25% reduction in emissions required by Part L2
• 23% increase in the assumed CO2 emissions from electricity (Part L1 and L2)
• New limits for solar gain in Part L2
• 25 - 60% increase in the cost of electricity expected by 2016 (Ofgem)

29. Part L2 (2010)
New drivers for passive cooling
• 25% reduction in emissions required by Part L2
• 23% increase in the assumed CO2 emissions from electricity (Part L1 and L2)
• New limits for solar gain in Part L2
• 25 - 60% increase in the cost of electricity expected by 2016 (Ofgem)
• Possible relaxation of peak internal temperature in
BCO specification (from 22°C to 25°C)

30. Flat slab with natural ventilation Coffered slab & underfloor ventilation
Hollowcore slab (Termodeck®) Water-cooled slab

31. Manchester University
Business School
Completion: 2011
Architect: Feilden Clegg Bradley
Precast, lattice girder floors with integral water cooling pipes.

32. Woodland Trust HQ, Lincolnshire
Completion: Autumn 2010
Architect: Feilden Clegg Bradley

33. Key messages:
• Compliance with Part L1 in 2010, 2013 & 2016 does not present any
particular issues for masonry/concrete housing.

34. Key messages:
• Compliance with Part L1 in 2010, 2013 & 2016 does not present any
particular issues for masonry/concrete housing.
• Heat recovery systems can help with 2010 and 2013 compliance and
avoid the need for costly renewables.

35. Key messages:
• Compliance with Part L1 in 2010, 2013 & 2016 does not present any
particular issues for masonry/concrete housing.
• Heat recovery systems can help with 2010 and 2013 compliance and
avoid the need for costly renewables.
• SAP now includes thermal mass, and shows a year-round round benefit
in highly insulated and airtight heavyweight dwellings.

36. Key messages:
• Compliance with Part L1 in 2010, 2013 & 2016 does not present any
particular issues for masonry/concrete housing.
• Heat recovery systems can help with 2010 and 2013 compliance and
avoid the need for costly renewables.
• SAP now includes thermal mass, and shows a year-round round benefit
in highly insulated and airtight heavyweight dwellings.
• The dwelling overheating check in SAP is likely to be revisited.

37. Key messages:
• Compliance with Part L1 in 2010, 2013 & 2016 does not present any
particular issues for masonry/concrete housing.
• Heat recovery systems can help with 2010 and 2013 compliance and
avoid the need for costly renewables.
• SAP now includes thermal mass, and shows a year-round round benefit
in highly insulated and airtight heavyweight dwellings.
• The dwelling overheating check in SAP is likely to be revisited.
• There is likely to be a move from air-conditioning to passive cooling
solutions in many new, non-domestic buildings.

38. Thank you
tdesaulles@concretecentre.com